No one has ever (seriously) said that Philly cast more votes than people of voting age. The claim has always been that the registration list, c. 1.1 million, was about the same as the total possible legal voters, but the number of ballots actually cast was only about 650-700,000. In other words, nowhere near the number of possible legal voters.
But 98% of the registered voters voting is a statistical impossiblity...and I believe that was the case in 2000. Anybody have info on that?